The present invention generally relates to automotive safety restraint devices and more particularly to air bags and systems.
The range of sizes of front seat passengers of a typical automobile varies from a relatively small infant in a child seat, to a small child to a large (male) adult. This range in occupant size makes the design of an effective occupant protection system extremely difficult, as a single system must operate within a changing environment. Typically, the air bag must inflate very quickly so that it is sufficiently inflated to protect an average sized adult occupant who is not wearing his or her seat belt, as defined by the current Federal Motor Vehicle Safety Standards (FMVSS) 208, while also operate in a manner so as not to injure the child or small-sized adult that might be improperly seated. Safety literature, as well as prior patents, has also addressed the need for designing safety systems that adequately protect the improperly seated child or adult. This improperly seated occupant is typically referred to as an out-of-position occupant, or alternatively, that the occupant is in an out-of-position orientation. Interestingly, the current Federal safety standards do not address system performance criteria in relation to the out-of-position child even though manufacturers have addressed this issue. The National Highway Traffic Safety Administration (see Federal Register, Vol. 63, No. 181, Sep. 18, 1998), which is incorporated herein by reference, has proposed new rules which include performance criteria for the out-of-position occupant such as a child, who is partially seated on the vehicle seat, with a portion of its anatomy lying upon or closely spaced from the air bag deployment location, typically the location of the air bag""s deployment door (see for example FIG. 12).
The proposed rulemaking proposes the addition of several new tests, including tests for various sized occupants that are positioned properly in the vehicle environment as well as in an out-of-position orientation.
Consider a rudimentary air bag system such as a passenger side air bag system. This system typically includes an inflator or gas generator capable of generating inflation gas at one determinable rate, an air bag and an optional deployment cover. The size of the air bag will vary with its application. As an example, the air bag may be of sufficient size to protect only the right outboard, front seated occupant and, in some applications, large enough to also protect an occupant in the middle front seating position. In order to protect the larger sized occupant, the inflator must be sized to generate gas at a sufficient rate to cause the air bag to burst through the deployment door and to inflate within a relatively few milliseconds to provide a cushioned barrier for the adult-sized, unbelted occupant. As can be appreciated, this type of aggressively positioned and inflated air bag may not be optimally suited for the out-of-position child or small adult. Various individuals have proposed systems which can accommodate each size of occupant including systems that automatically or manually deactivate the passenger side air bag or otherwise change the performance characteristics of the system, in particular the inflator, in proportion to the size and position of the occupant. For example, such systems would be deactivated when a child or alternatively, an infant seat, is present in the front or facing passenger seating position. The deactivation of the air bag may be done manually or through a complicated array of position sensors and associated software algorithms which determine the size and location of the occupant. As can be appreciated, these approaches have their drawbacks in that a manually deactivated system may not be subsequently reactivated or, alternatively, the active occupant sensing system is relatively expensive. Other solutions to the above problem propose utilizing a multi-stage air bag inflator in which the air bag is inflated at a low inflation rate, in the presence of a child, out-of-position occupant, child seat or small adult, and inflated at a higher rate in other conditions.
The present invention provides a unique and simple solution to the design of an air bag and air bag system capable of protecting the wide range of vehicle occupants of different sizes in a severe crash.
It is an object of the present invention to provide an improved air bag system comprising a multi-chambered air bag activated by a single stage inflator, however multi-stage inflators can also be used.
It is a further object of the present invention to provide protection to normally seated occupants while minimizing the risk of injury to out-of-position occupants, in particular, children.
Accordingly the invention comprises: a partitioned air bag comprising an upper and a lower inflatable chamber, the lower chamber upon inflation is positioned to provide a cushioned boundary generally against the lower chest and abdomen of a seated adult occupant to be protected, the lower chamber first receiving inflation gas from a source of inflation wherein the inflation gas is sequentially transferred to the upper chamber through one or more ports or passages formed by or in a separator panel. The separator panel separates the air bag into the upper and lower chambers. The source of inflation is preferably a single stage air bag inflator characterized as having a relatively low fill rate.